Thread trimmer for sewing machines



Sept. 15, 1942. A. F. RUNGE 2,296,190

THREAD TRIMMER FOR SEWING MACHINES Filed Aug. 19, 1941 Patented Sept. 15, 1942 UNITED STATES PATENT OFFICE 2,290,190 marina ranmaa roa sswmo moms Alfred F. Range, Lebanon, Tenn. Application August 19, 1941, Serial No. 407,478

'attachments usually comprise merely a blade member attached to the shaft of the presser foot, across which the user of the machine draws the thread after the material has passed rearwardly from beneath the presser foot and in so doing it is a frequent occurrence to have the thread drag upon the needle so that the same may become bent or broken and it also frequently happens that after the thread has been cut and has dropped back loose upon the table of the machine, it gets accidentally drawn through the eye of the needle so that the latter is unthreaded and it is necessary for the operator to stop and rethread the needle before she can proceed with her work.

A principal object of the present invention is to provide a thread cutting attachment which is secured to the presser foot of the machine in a position which will make it convenient for the operator to draw the thread up over the cutting blade or knife after the material has passed from beneath the presser foot and which is so designed that the ends of the thread leading from the needle and from the bobbin will be securely held until the operator is ready to start work upon another piece of material.

Another object of the invention is to provide a thread cutting attachment for a sewing machine having in association with a cutting blade, a resilient thread gripping means between which the threads are drawn as the material is lifted from the machine table to be cut by the blade, and are gripped or securely held so that when the necessary pressure ie applied to the threadto draw them across the cutting blade, the threads will be out without imposing a strain upon the needle and thus the bending or breaking of the needle will be prevented and, in addition, as previously stated, the threads will be held so that the needle will not become unthreaded accidentally and .the bobbin thread cannot be drawn back into the bobbin case beneath the machine table and thereby retard the operator in the performance of her work.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawing, it being understood, however, that the.

invention is not to be considered as limited by 8 Claims. (01. 112-252) the specific illustration or description but that such illustration and description constitutes a preferred embodiment of the invention.

In the drawing:

Figure 1 is a view in side elevation of the lower portion of a presser foot showing one embodiment of the present invention applied thereto, the securing screw being in section.

Figure 2 is a view in horizontal section through the shaft of the presser foot looking down upon the cutter.

Figure 3 is a view in bottom plan of the cutter per se.

Figure 4 is a sectional view on the line 4-4 of Figure 1.

Figure 5 is a view in side elevation of another embodiment of the invention, showing the same applied to a presser foot.

Figure 6 is a transverse section through the shaft of the presser footshown in Figure 5 looking down upon and showing the thread cutter and securing means in top plan.

Referring now more particularly to the drawing, the numeral I indicates the usual post upon which is mounted the sewing machine presser foot 2 which operates in the well known manner in association with the needle 3. In certain types of sewing machines the presser foot is secured to the post i by a screw 4 which is inserted into a threaded aperture in the side of the post I and passes through a slot 5 formed in a sleeve 6 I which is an integral part of the presser foot. The

screw 4 is provided with a knurled head 1 byv means of which it may be tightened up or loosened by hand as desired.

In accordance with the present invention the embodiment of the same-as designed for application to the style of presser foot shown in Figure 1, comprises a flat plate 8 having a slot 9- cut therein, from one edge, in a transverse direction to receive the screw 4, by means of which the plate is secured firmly in vertical position, against the side of the sleeve 6 which forms a part of the presser foot.

Formed integrally with the bottom edge of the plate 8 is an upturned flange portion Ill and this has secured between it and the body 8 the ends of two flat spring loops II and I2 which lie in side by side contacting relation as shown in Figures 2 and 3, thus providing a bight portion l3 which is rearwardly directed and between which the ends of threads are drawn for the purpose of severing the same as hereinafter described.

Disposed against the side of the plate 8 above the upturned edge of the flange I0 is a knife plate I! which has a lateralblade i5 formed integral with its lower edge and sharpened at one end to form the cutting edge l6 which is directed obliquely across the flange l8 and forming with the adjacent end of the plate It the gullet I! which is substantially in line with the adjacent faces of the two looped springs and into which the thread is drawn. This plate i4 is secured in a suitable manner to the plate I, as,.for example, by the use of the screw it.

As is readily seen. each of the loop springs comprises a single length of ribbon like spring cated horizontally upon the top edges of the ends of the spring loops and thus a thread or threads when drawn upwardly at the rear of the cutter and then pulled forwardly will be drawn between the springs and will be cut adjacent the top edges thereof so that the ends of the threads running to the machine needle and to the bobbin will be held securely after the material is removed.

In Figures 5 and '6, a slightly modified embodiment of the invention is illustrated, which embodiment is designed for attachment to those machines in which the presser foot, indicated by the numeral l9, carries a circular sleeve 20 for the reception -of a circular post 2|, and is secured to the post by the set screw 22 passing through the rear portion of the sleeve instead of through the side. In this form of the invention there is provided the plate body 23 having the slightly arcuate flange 24 in which is formed a suitable opening, not shown, to receive the set screw so that the arcuate portion may be bound securely against the rear side of the sleeve 20.

An upturned bottom edge flange 25 secures to the plate body 23 a pair of spring loops 26 and 21 which, as shown in Figure 6, are of the same form and-design and placed in side by side relation in the same manner as the springs or loops shown in the embodiment illustration in Fi e 2.

The body plate 23 has secured thereto a cutter plate 28 which extends rearwardly over the tops of the spring loops and at its rear end has formed integrally therewith the lateral knife flange 29 in the rear edge of which is formed a V recess 20, the converging edges of which are sharpened, as shown, to provide cutting edges. With this embodiment, as in the form shown in Figures 1 to '3 inclusive, the threads are severed by the operator lifting the material from the machine table after it has passed rearwardly from beneath the presser foot, and bringing the threads up between the adjacent sides of the spring loops and then drawing them forwardly into the V knife to be severed thereby. The

remaining thread ends will thus be firmly held between the springs.

From the foregoing it will be readily apparent that the invention as illustrated in the two embodiments here shown and described, when in use, functions to save the time of the operator because of the fact that the operator does not have to stop and pick up scissors or a razor blade or other device to cut the threads or to break amount of thread as the same can be cut of! close to the material whereas the usual procedure is to draw out a long piece of thread from the bobbin and through the needle and then cut the same at a distance from the material, and finally the garment leaves the machine in a cleaner condition than is usually the case as there are not the usual long thread ends which have to be subsequently trimmed off.

I claim: 1. A thread cutting attachment for the presser foot of a sewing machine in which the presser foot is secured by a screw, comprising a plate, means for coupling the plate to the presser foot by said screw, 2. pair of spring members carried by the plate inside by side relation and designed to facilitate the drawing of a thread therebetween to be resiliently engaged thereby, and a cutting blade secured to the plate above said springs and having a cutting edge extending across the contacting portions of the springs.

2. A thread cutting attachment as set forth in claim 1, in which said springs comprise two bands of resilient material, each bent upon itself to form a loop, the loops being secured in side by side relation to form abight into which the thread is drawn in moving it toward the cutting edge of said blade.

3. A thread cutter attachment for a presser foot of a sewing machine, comprising a plate body, means for securing said body vertically to the presser foot to extend rearwardly therefrom, means forming a pair of looped springs secured in side by side relation to the plate to extend horizontally, said springs having adjacent portions between which a thread may be yieldably held, and a cutting knife secured to the body horizontally above said springs and having a rearwardly directed V cutting edge arranged to have its center substantially aligned with the contacting faces of the springs.

4. A thread cutter attachment fora presser foot of a sewing machine, comprising a plate body, means for securing said body vertically to the presser foot to extend rearwardly therefrom, means forming a pair of looped springs secured in side by side relation to the plate to extend horizontally, said springs having adjacent portions between which a thread may be yieldably held, a cutting blade secured to said body to extend horizontally therefrom in a plane lying above and in close proximity to the tops of said springs, said blade having its rearwardly directed edge sharpened to provide a cutting edge extending transversely with respect to the line of contact between the adjacent portions of the springs.

5. A thread trimmer attachment for a sewing machine, comprising a plate, means for attaching the plate to the machine, a blade carried by the plate and having a cutting edge horizontally disposed when the plate is attached, and a pair of looped springs arranged in side by side contacting relation to form a V bight into which a thread may be drawn and frictionally held, said springs being secured to the plate below the blade and the blade being disposed with the cutting edge extending across and located inwardly of the crotch of said bight.

- 6. A thread trimmer attachment for a sewing machine, comprising a plate, means for attaching the plate to the machine, a blade carried by the plate and having a cutting edge horizontally disposed when the plate is attached, and a pair of springs each formed intoa closed loop, the ends the threads by hand; it also saves a considerable of the two loops being disposed in side by side relation and secured to the plate below the blade, theloops being in side by side relation and meeting to form an open V bight into which a thread may be drawn and frictionally held, and said blade having the cutting edge extending across and located inwardly of the crotch of said bight.

'7. The thread trimmer attachment as set forth in claim 6 wherein said springs are formed of ribhon-like material and have the wide races or the ends in opposing relation and said blade lies upon the dges of the springs.

8. A thread trimmer for attachment to a sewing machine, comprising a plate, means for securing the plate vertically to a machine, an upturned flange secured along the bottom edge of the plate, a pair of springs each formed into a closed loop, the ends of the two loops being disposed in side by side relation and secured between the flangeand plate, the loops being in side by side relation and coacting to form a V bight into which a thread may be drawn and frictionally held,-and a cutting blade having a vertical portion secured to one side of the plate and a horizontal portion lying over the secured ends of the loops, said horizontal portion having a cutting edge extending across the said ends of the two loops inwardly of the crotch of the bight;

ALFRED F. RUNGE. 

